I had tested LemonSwan as end user and noticed its matching algorithm uses the Big Five normative personality test to assess personality of daters.

Unfortunately the Big Five normative personality test is obsolete, has been proven as an incomplete and incorrect model of personality
SINCE YEAR 2000!!! 17 long years ago!Now it is obsolete and a fraud to use the Big Five normative personality test!The Big Five (Big5, OCEAN, Five Factor Model) normative personality test is the biggest mistake Psychologists made since several years ago.The Big Five is also known as the Five Factor Model theory of personality traits, a psychological model based on research by Paul Costa and Robert McCrae.

Unless they can prove their method can match prospective partners who will have more stable and satisfying relationships (and very low divorce rates) than couples matched by chance, astrological destiny, personal preferences, searching on one's own, or other technique as the control group in a peer reviewed Scientific Paper for the majority (over 90%) of the members of the site: It is a HOAX, a big FRAUD.